Field of the Invention
Apparatuses and methods consistent with the present disclosure relate to an image forming apparatus and a fuser driving control method, and more particularly, to an image forming apparatus and a fuser driving control method capable of controlling a plurality of heater units by different schemes according to a temperature range of a heating roller.
Description of the Related Art
An image forming apparatus means an apparatus that prints printing data generated from a printing control terminal apparatus like a computer on printing paper. An example of the image forming apparatus may include a copier, a printer, a facsimile, a multi function peripheral (MFP) in which functions of them are compositely implemented in one apparatus, etc.
The image forming apparatus may form an image by various schemes. As one of them, an electro photography scheme is used. In the image forming apparatuses such as a copier and a printer to which the electro photography scheme is applied, photoconductors having a drum form are simultaneously charged, the photoconductors are exposed to light controlled depending on image information, an electrostatic latent image is formed on the photoconductor, a visible image (toner image) is formed by selective adsorption with the electrostatic latent image of the toner, the toner image is transferred to recording paper, and a recording medium on which the transfer is performed passes through a fuser to fuse the toner image on the recording medium, thereby forming the image.
The image forming apparatus may adopt a configuration of finally fusing an image on printing paper. The configuration is called the fuser. Generally, the fuser is configured to include a heating roller having a heater and a pressure roller in pressing contact with the heating roller to be rotatably driven.
The fuser needs to be maintained at appropriate temperature and pressure. In this case, if a temperature of a nip part is too low, a toner layer does not reach a temperature range of glass transition and thus a cold offset to hinder the toner layer from being fused to the recording medium occurs and the non-fused toner may contaminate peripheral parts to damage printed images and parts. In contrast, if the temperature of the nip part is too high, release property between a roller and a toner is greatly reduced and thus a hot offset to stick some of the toner to the roller occurs.
Further, after a nip is notified, a curl occurs in paper. The curl amount is increased as the temperature is generally increased. Therefore, the high temperature increases the curl amount of paper to increase a jam occurrence frequency. Further, when the high temperature is maintained for a long time, a lifespan of the fuser may be reduced and energy may be excessively consumed. Therefore, a heat quantity control of the heater to maintain a temperature of the fuser at an appropriate level is one of the important areas of the development of the image fuser in terms of the improvement in quality of the printed image, the lifespan of the fuser, and the energy efficiency.
Meanwhile, the heater positioned in the heating roller is configured in plural to adaptively provide heat to paper having various widths. In detail, a dual type heater in which a heat distribution of one heater is concentrated on a central portion and a heat distribution of the other heater is concentrated on both end portions has been widely used. Therefore, a temperature sensor of the fuser is configured in plural to measure the temperature of the central portion of the heating roller and the temperature of both end portions thereof, respectively.
As the existing temperature sensor, a contacting sensor operated by contacting the heating roller is used. In this case, image deterioration like a printing gloss deviation due to a difference in temperature between a portion that the temperature sensor contacts and a portion that the temperature sensor does not contact may occur. To improve the image deterioration, a non-contacting sensor is used, which incurs an increase in material costs.
Meanwhile, the sensor positioned at the central portion of the heating roller is positioned in a notification area through which the printing paper passes, and therefore the use of a non-contacting sensor may not be avoided to prevent the image deterioration due to the sensor contact. However, a side sensor positioned at the end portion may be positioned in the notification area or the non-notification area. When the side sensor is positioned in the non-notification area, the effect due to the sensor contact is not generated in the printed image, and therefore the contacting sensor may be used.
However, the contacting sensor is positioned in the non-notification area, and therefore it is difficult to accurately control the heaters of both end portions to the wanted temperature. Therefore, even when the contacting sensor and the non-contacting sensor are used together, a method for appropriately controlling temperature is required.